Film developing machine



March 22, 19381. 'w DOUDEN 7 2,111,759

FILM DEVELOPING MACHINE Filed Aug. 31, 1934 2 Sheets-Sheet l 0 ISnnentorVVilliam L. Douala,

' attorney a.rcl1122,1938. D DE 2,111,759;

FILM DEVELOPING MACHINE Filed Aug. 31, 1934 2 Sheets-Sheet 2 "nmlmmmmmZ5 llllllllll ll i mm I I 7 ATTORNEY Patented Mar. 22, 1938 FIIMDEVELQPIN G MACHINE William L. Douden, New York, N. Y., assignor toRadio Corporation of America, a corporation of Delaware ApplicationAugust 31,

6 Claims.

The present invention relates to an improvement in film developingmachines, and more particularly to an improvement in the type of suchmachines used in the continuous high-speed development of motion picturefilms. The present invention also involves a novel method of developingfilms, included in the operation of such machines but which can beperformed independently thereof and which is claimed in my divisionalapplication Serial No. 117,350, filed December 23,1936. I

It has heretofore been customary in the art to pass motion picture filmthrough a series of tanks or tubes of developing fluids under thecontrol of driving sprockets or rolls, the film being passed downwardlyinto the various fluids, upwardly therefrom,- and again downwardly fromthe air,

into fluid until the termination of the process.

Such procedure is particularly objectionable in the case of motionpicture film, which is perfo rated at the edges with" sprocket holes, asthe sprocket holes retain air and carry it into the developer. Allphotographic developers are notoriously subject to oxidation, since;from their very nature, they are required to be powerful (althoughcontrollable) reducing agents. As a consequence, the carrying of air andoxygen into the developer and other baths by the film shortens the lifeof the developer, and, due to the irregular oxidation by the airbubbles, tends to produce irregular development resulting ,in spots, andstreaks on the fllm. This is particularly annoying in the case ofcombined sound and picture film, where the spots and streaks produceloud pops and bangs in the sound reproduction from the photographicsound track.

One object of the present invention is to provide a developing machinewhich will prevent the introduction of air into any of the fluid bathsused in treating the film.

Another object of my invention is the provision of a developing machinewhich eliminates air or gas bubbles from the fluid baths.

Another object of my invention is to provide a developing machine whichtreats the film at less than atmospheric pressure.

Another object of my invention-is. to provide a developing machine whichis substantially proof against leakage.

Another objectof my invention is to provide such a machine which can bereadily cleaned. Other and ancillary objects of my invention will beapparent to those skilled in the art from an inspection of theaccompanying drawings and reading of the accompanying specification.

1934, Serial No. 742,203

In the drawings: A

Figure 1 shows a longitudinal section of a preferred form" of myinvention;

Figure 2 shows a second form of my invention;

Figure 3 shows a transverse section thereof, and 5 Figure 4 shows apreferred detail applicable to both of the above forms: 7

As will be-apparent from a casual inspection of these drawings, one ofthe major features of my invention is the complete processing of thefilm 10 in a partial or complete toricellian vacuum, where the highestpressure to which the film is subjected is approximately that of theatmosphere and the lowest pressure approximates that of the vaporpressure of the developer at the temperature of development.

Referring first to Fig. 1: The film F passes into the apparatus, forexample, from left to right as indicated over an idler roller and intothe fluid D contained within the tank I, and the level of which ismaintained by the inlet pipe b which the supply is provided from thesupply t I nk.

T e film' passes around an appropriately-bearinged corrosion-proof idlerroller 2' and upwardly into the developing tube 3. This developing tubemay be made of any desired material, but for negative film I prefer tomake it of- Monel metal or hard rubber, which are opaque andcorrosionresisting; while for positive film I prefer to make it ofastrong corrosion-resisting glass such, for example, as that known underthe trade name of Pyrex in order to permit inspection of the film duringdevelopment, as the positive film' may be safely handled in a relativelystrong yellow light.

Near the top of the tube the film passes over,35 an idler roller 4 whichis supported from a float 5 in the fluid. It will be apparent that,since the :roller 4 is supported by the float 5, the film can never besupported above the fluid level in the tube. The float may preferably bemade of par- 40 afiined: cork or balsa wood, or hollow, and of Monelmetal, hard rugber, or plated copper or brass, but.

tracting proper quantities of fluid from the tubes and maintaining anappropriate vacuum.

An extraction pipe 6 is provided, preferably connected to a pump andextraction system of any known or desired type withdrawing apredetermined quantity of fluidper unit of time or influx, andpreferably irrespective of the gaseous content thereof; i. e., such asgas-well clearingpumps and the like.

Above the influx level of .the pipe 6, there is preferably provided asecond effusion pipe I connected to a second manifold tand which, inturn, is connected to a second pumping system of known type adapted andadjusted to maintain a predetermined pressure difference betweenatmospheric pressure and the exhaust pressure, in order to maintain aconstant fluid level. Such a system may be comprised, for example, of arelatively large capacity exhaust pump and either a control or a reliefvalve governed by atmospheric pressure to maintain a constant pressuredifference; the large capacity of the exhaust pump being desired toprovide for the initial elimination of dissolved gases, and such gases'as might be accidentally introduced.

ment of the film.

The film passes downwardly through the tube 3 to the idler 2, which isidentical with 2', and thence upwardly to the driving sprocket I0 whichforms of my invention inthe form of a hinged trough. The trough ispreferably supported at one side by the bracket 2| and pivoted at 22,and is supported, at the other side by a movable member 23 which fitsbeneath a catch 24.

When it is desired to clean the apparatus, the trough I is raisedslightly to release the member 23 from the catch 24, the member 23 ispulled is illustrated as slightly above the fluid level, for

reasons hereinafter described. In order to secure the simple film driveshown in Fig. 4 wherein the sprocket shafts 26 are driven through ahelical gear from the line shaft 21, the driving sprockets are shown aslocated above the..,fluid level. It will be, apparent, however, that'ifother driving means. are substituted such, for example, as corrosionresisting chains or gears, the-sprockets may be immersed in the fluidand the film kept continually immersed during'the entire process.

In the successive elements of the apparatus, the corresponding parts aredesignated by identical reference numerals 2 to ill inclusive, and thepipes 6 and l are respectively connected to the manifolds 8 and 9.

It is apparent that if fluids of different density are to be used forthe same time,or fluids of incommensurate density for incommensurateunits of,time, the manifolds must be corre-' spondingly subdivided andcontrolled, or the lengths of the tubes selected or controlled, or

' both.

backwardly and the trough l is permitted to hang from the pivot 22,thereby emptying its contents into a trough 25 formed in the floor ofthe 'room housing the apparatus and permitting a thorough scrubbing notonly of the trough l but of the tubes or tanks 3.

Having now described my invention, I claim:

1. In a developing machine, a liquid receptacle, and a film treatingchamber closed at its upper end and extending upwardly therefrom andadaptedto contain a liquid maintained by atmospheric pressure, wherebyfilm may be passed continuously through the region of reduced pressureat the upper end of said receptacle.

2. A developing machine comprising a liquid treating container, meansfor immersing the lower end thereof in liquid, and means for producing apressure below that of the atmosphere within treating container, meansfor immersing the lower end thereof in liquid, means for withdrawingliquid from the upper end thereof, and means for producing a pressurebelow that of the atmosphere within the upper end thereof, whereby filmmay be passed continuously through the region of reduced pressure at theupper end of said container.

4. A developing machine comprising a receptacle for liquids having itslower end open and its upper end closed to the surrounding atmosphere,means for passing film through said receptacle, and means formaintaining liquid within {I'he fluid level maybe controlled in anyappropriate manner either by control of the exhaust apparatus or by theprovision of an exterior tank as shown in 'sig. 1, and this fluid levelis generally indicated at 3!, the film being withdrawn through anappropriate trap 32. The inlet pipe is the same as that shown in Fig. 1.

As shown in Fig.3, the film may be threaded said receptacle, wherebyfilm may be passed continuously through the region of reduced pressureat the upper end of said receptacle.

5. A developing machine comprising an inverted tank, a troughtherebeneath and covering the lower end thereof for maintaining fluidtherein, means supporting said trough in such a manner that it isremovable from said covering position, and means for passing a strip offilm through said trough and tank, whereby fllm may be passedcontinuously through the region of reduced pressure at the upper end ofsaid tank.

6. A developing machine comprising a liquid treating chamber maintainedat less than atmospheric pressure, and means including a liquid seal forpassing film therethrough, whereby film may be passed continuouslythrough the region of reduced pressure at the upper end of said chamber.

WILLIAM L. DOUDEN.

